RF-45 CNC Advice needed

[eartaker]

So after having the X2 CNCed for a year now I need something bigger. I have decided to go with the RF-45 and I want to do it right this time. I am looking at the Keling KL34-180-90 1125oz Servo motors, the Gecko G320X Drivers, CNC4PC C11G breakout board. but I'm not sure on what else I will need for electronics. Do I need encoders? Would it be better to use Stepper motors?

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[Flenser]

I have the Keling 1125 in-oz servos, though they have not been mounted yet. They are probably overkill for the 45, but they will do the job. I don't know if steppers would work well on this machine. To get the power up you will need to go with bigger and slower motors which could be annoying with the long x travel IMO.

You need encoders. I'm using (hopefully) the US-Digital encoders Keling sells, but they have quite the bad reputation on this board. It has an unusually low current draw making it difficult to noise proof. There is another encoder Digikey sells that gets more respect, but I forget the name.

You will also need a power supply. This is what I bought - after reading that others were using it.

There are a ton of RF-45 threads gong right now. This one and this one have some good info on motors and encoders.

Jeff

[eartaker]

Awesome so servos it is, I found the Digikey encoders 102-1307-ND. What ball screws and ball nuts did you go with?

[Flenser]

I bought ball screws from linearmotionbearings on ebay. The seller has a good reputation on this board, and more importantly his ball screws are super cheap! I plan to machine the ends myself, but he does offer custom machining at reasonable prices. These are rolled C7 screws, BTW. There are definitely higher quality alternatives if you are willing to pay more.

[mattmark]

So after having the X2 CNCed for a year now I need something bigger. I have decided to go with the RF-45 and I want to do it right this time. I am looking at the Keling KL34-180-90 1125oz Servo motors, the Gecko G320X Drivers, CNC4PC C11G breakout board. but I'm not sure on what else I will need for electronics. Do I need encoders? Would it be better to use Stepper motors?

What Jeff said

I also picked up ballscrews from linearmotionbearings2008 from ebay.. haven't tried them / measured them for error/backlash yet though. i also picked up their bearing blocks (only bought one side/ the motor side).

The CUI AMT-102V encoders work really well.

I'd take a read at Bob W's electronics page: http://www.cnccookbook.com/CCMillCNCElectronics.html

Getting set up to get the motors working is reasonable, but i'm in the phase of getting everything up to safety and for monitoring - I bought the Master Control Board from CNC4PC - the C17 board.

Which computer cpu are you going to be running off of? and are you planning to use the printer port? A lot of people have been going USB via the SmoothStepper (not a lot of documentation on the site: http://www.warp9td.com/ ), if you want to go laptop or get a higher pulse rate going..

[eartaker]

I have been using the parallel port with my X2 but will probably go USB. Not sure on the computer yet ill throw another one together. might go with a mini ITX 2Ghz dual core so i can put it in the controller box. I have looked at this supplier for ball screws but what size and pitch did you go with?

[mattmark]

I have been using the parallel port with my X2 but will probably go USB. Not sure on the computer yet ill throw another one together. might go with a mini ITX 2Ghz dual core so i can put it in the controller box. I have looked at this supplier for ball screws but what size and pitch did you go with?

hey eartaker,

I went with 20mm ballscrews at 5mm pitch for all axis' (some would consider 25mm for Z). the end blocks (2 a/c bearings from what i know) are 15mm and the finished ends for the pulleys are at 10mm

matt

[pete from TN]

That is basically what I am using, Antek multi voltage power supply, CNC4PC C11G breakout board, Three G320's, The AMT encoders( WHICH ARE AWESOME), And some Keling INc. 1125 oz inch motors. Mine is very powerful with this setup and has worked well despite my hamfisted attempts at blowing stuff up and crashing things into other immovable things it continues to amaze. I get some decent rapids( I actually turn it down to be a little safer) and there is more than enough power on tap to break endmills without a seconds thought. I did manage to blow up two geckos along the way but that is my inexperience talking and not any fault of the setup. I do not see how you can go wrong with this.....

You will really love the servos, they are amazing and nearly silent in operation, and once I got my steps per right I am getting some very accurate results for a homebuilt machine. I do recommend a slightly higher ratio for the Z axis and when you are in there make every effort to lock down the Z axis slide to the ballscrew mount. I did the mods that IH recommends and even went a little further, you can see what I did on my build thread. There is some difficulty getting the Z tight due to it's weight and I used a 3/4 inch ballscrew on the Z just to be sure. I used 5/8 inch screws on the X and Y and they are more than adequate for the size of this machine. When you make the Z top motor mount make sure you leave enough meat below the angular contact bearings to take the constant lifting of that heavy head. I chose to make all of my mount plates from 3/4 inch aluminum and the bearing pockets are not that deep so no worries.... The funny thing is none of this is hard to do but if you do not get all of it right you will be chasing little fidgety bull**** forever..... Do it right the first time and take your time. Also I HIGHLY recommend doing the one shot oiler setup with at least a manual pump. It makes a world of difference in the operation of the machine and allows you to run your gibs a little tighter.

If you are gonna run flood coolant like me I took a page from the IH setup with running the wiring inside surgical tubing and route everything with brass hose barbs. This is a real good idea and makes another little thing less of a worry, chafing on the wires from the machine running back and forth constantly is much improved. Another thing I recommend is take the time to finish your limits and homes if you intend to use them before you start running the machine, if I did that I would not have burnt out that gecko. I understand you already have a cnc mill so that may not really apply to you depending on your confidence level.

These are wonderful machines and at this size capable of some real metal removal. You will be pleasantly surprised for sure..... Good luck and if I can help you don't hesitate to ask.... peace

Pete

[eartaker]

Well Pete your Post on your ZX45 is where I got the ideas for what parts to use =]

Thanks for all of the input. I have ordered the motors and encoders. I went to place the order for the Gecko G320X's but they are out of stock. I will call them today. Hope they will have them in soon. I guess the only part I'm still in the dark about is the breakout board. The C11G looks good and has a built in charge pump. I eventually would like to fully automate the spindle control. I have also been looking at the smoothstepper board with the C25 breakout board. Witch one of these would you suggest? Also what would I need to automate the spindle control? I have seen that some have used with C6 board with the C3 on the X2's but I'm guessing I will need something to drive a VFD for the RF-45.

Jermie

[mattmark]

Well Pete your Post on your ZX45 is where I got the ideas for what parts to use =]

Thanks for all of the input. I have ordered the motors and encoders. I went to place the order for the Gecko G320X's but they are out of stock. I will call them today. Hope they will have them in soon. I guess the only part I'm still in the dark about is the breakout board. The C11G looks good and has a built in charge pump. I eventually would like to fully automate the spindle control. I have also been looking at the smoothstepper board with the C25 breakout board. Witch one of these would you suggest? Also what would I need to automate the spindle control? I have seen that some have used with C6 board with the C3 on the X2's but I'm guessing I will need something to drive a VFD for the RF-45.

Jermie

Hi Jermie,

Where did you try and order the Geckos? If from Gecko directly, try KelingInc.net. if you're looking at the smoothstepper, from what i know the c25 is what most of us have. i bought the c6 to do spindle control and a teco 7300cv VFD (for a baldor 3hp 3 phase motor).. c15 for coolant control.. these are all still sitting idle as i finish the main cncing of the machine..

Matt

[Flenser]

Funny, I'm pretty sure the G320x's I ordered from Keling were drop shipped from CNC4PC. Not sure if that's the normal procedure for Keling. They were missing from a larger shipment, and I had to ask for them before they were shipped.

Jeff

[eartaker]

I tried ordering from Gecko, I guess I will have to call Keling and modify my order b4 they ship it.